llvm/lib/Support/YAMLTraits.cpp

   1 //===- lib/Support/YAMLTraits.cpp -----------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/Support/YAMLTraits.h"
  10 #include "llvm/ADT/STLExtras.h"
  11 #include "llvm/ADT/SmallString.h"
  12 #include "llvm/ADT/StringExtras.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/ADT/Twine.h"
  15 #include "llvm/Support/Casting.h"
  16 #include "llvm/Support/Errc.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18 #include "llvm/Support/Format.h"
  19 #include "llvm/Support/LineIterator.h"
  20 #include "llvm/Support/MemoryBuffer.h"
  21 #include "llvm/Support/Unicode.h"
  22 #include "llvm/Support/YAMLParser.h"
  23 #include "llvm/Support/raw_ostream.h"
  24 #include <algorithm>
  25 #include <cassert>
  26 #include <cstdint>
  27 #include <cstdlib>
  28 #include <cstring>
  29 #include <string>
  30 #include <vector>
  31
  32 using namespace llvm;
  33 using namespace yaml;
  34
  35 //===----------------------------------------------------------------------===//
  36 //  IO
  37 //===----------------------------------------------------------------------===//
  38
  39 IO::IO(void *Context) : Ctxt(Context) {}
  40
  41 IO::~IO() = default;
  42
  43 void *IO::getContext() const {
  44   return Ctxt;
  45 }
  46
  47 void IO::setContext(void *Context) {
  48   Ctxt = Context;
  49 }
  50
  51 void IO::setAllowUnknownKeys(bool Allow) {
  52   llvm_unreachable("Only supported for Input");
  53 }
  54
  55 //===----------------------------------------------------------------------===//
  56 //  Input
  57 //===----------------------------------------------------------------------===//
  58
  59 Input::Input(StringRef InputContent, void *Ctxt,
  60              SourceMgr::DiagHandlerTy DiagHandler, void *DiagHandlerCtxt)
  61     : IO(Ctxt), Strm(new Stream(InputContent, SrcMgr, false, &EC)) {
  62   if (DiagHandler)
  63     SrcMgr.setDiagHandler(DiagHandler, DiagHandlerCtxt);
  64   DocIterator = Strm->begin();
  65 }
  66
  67 Input::Input(MemoryBufferRef Input, void *Ctxt,
  68              SourceMgr::DiagHandlerTy DiagHandler, void *DiagHandlerCtxt)
  69     : IO(Ctxt), Strm(new Stream(Input, SrcMgr, false, &EC)) {
  70   if (DiagHandler)
  71     SrcMgr.setDiagHandler(DiagHandler, DiagHandlerCtxt);
  72   DocIterator = Strm->begin();
  73 }
  74
  75 Input::~Input() = default;
  76
  77 std::error_code Input::error() { return EC; }
  78
  79 // Pin the vtables to this file.
  80 void Input::HNode::anchor() {}
  81 void Input::EmptyHNode::anchor() {}
  82 void Input::ScalarHNode::anchor() {}
  83 void Input::MapHNode::anchor() {}
  84 void Input::SequenceHNode::anchor() {}
  85
  86 bool Input::outputting() const {
  87   return false;
  88 }
  89
  90 bool Input::setCurrentDocument() {
  91   if (DocIterator != Strm->end()) {
  92     Node *N = DocIterator->getRoot();
  93     if (!N) {
  94       EC = make_error_code(errc::invalid_argument);
  95       return false;
  96     }
  97
  98     if (isa<NullNode>(N)) {
  99       // Empty files are allowed and ignored
 100       ++DocIterator;
 101       return setCurrentDocument();
 102     }
 103     TopNode = createHNodes(N);
 104     CurrentNode = TopNode.get();
 105     return true;
 106   }
 107   return false;
 108 }
 109
 110 bool Input::nextDocument() {
 111   return ++DocIterator != Strm->end();
 112 }
 113
 114 const Node *Input::getCurrentNode() const {
 115   return CurrentNode ? CurrentNode->_node : nullptr;
 116 }
 117
 118 bool Input::mapTag(StringRef Tag, bool Default) {
 119   // CurrentNode can be null if setCurrentDocument() was unable to
 120   // parse the document because it was invalid or empty.
 121   if (!CurrentNode)
 122     return false;
 123
 124   std::string foundTag = CurrentNode->_node->getVerbatimTag();
 125   if (foundTag.empty()) {
 126     // If no tag found and 'Tag' is the default, say it was found.
 127     return Default;
 128   }
 129   // Return true iff found tag matches supplied tag.
 130   return Tag.equals(foundTag);
 131 }
 132
 133 void Input::beginMapping() {
 134   if (EC)
 135     return;
 136   // CurrentNode can be null if the document is empty.
 137   MapHNode *MN = dyn_cast_or_null<MapHNode>(CurrentNode);
 138   if (MN) {
 139     MN->ValidKeys.clear();
 140   }
 141 }
 142
 143 std::vector<StringRef> Input::keys() {
 144   MapHNode *MN = dyn_cast<MapHNode>(CurrentNode);
 145   std::vector<StringRef> Ret;
 146   if (!MN) {
 147     setError(CurrentNode, "not a mapping");
 148     return Ret;
 149   }
 150   for (auto &P : MN->Mapping)
 151     Ret.push_back(P.first());
 152   return Ret;
 153 }
 154
 155 bool Input::preflightKey(const char *Key, bool Required, bool, bool &UseDefault,
 156                          void *&SaveInfo) {
 157   UseDefault = false;
 158   if (EC)
 159     return false;
 160
 161   // CurrentNode is null for empty documents, which is an error in case required
 162   // nodes are present.
 163   if (!CurrentNode) {
 164     if (Required)
 165       EC = make_error_code(errc::invalid_argument);
 166     return false;
 167   }
 168
 169   MapHNode *MN = dyn_cast<MapHNode>(CurrentNode);
 170   if (!MN) {
 171     if (Required || !isa<EmptyHNode>(CurrentNode))
 172       setError(CurrentNode, "not a mapping");
 173     else
 174       UseDefault = true;
 175     return false;
 176   }
 177   MN->ValidKeys.push_back(Key);
 178   HNode *Value = MN->Mapping[Key].first.get();
 179   if (!Value) {
 180     if (Required)
 181       setError(CurrentNode, Twine("missing required key '") + Key + "'");
 182     else
 183       UseDefault = true;
 184     return false;
 185   }
 186   SaveInfo = CurrentNode;
 187   CurrentNode = Value;
 188   return true;
 189 }
 190
 191 void Input::postflightKey(void *saveInfo) {
 192   CurrentNode = reinterpret_cast<HNode *>(saveInfo);
 193 }
 194
 195 void Input::endMapping() {
 196   if (EC)
 197     return;
 198   // CurrentNode can be null if the document is empty.
 199   MapHNode *MN = dyn_cast_or_null<MapHNode>(CurrentNode);
 200   if (!MN)
 201     return;
 202   for (const auto &NN : MN->Mapping) {
 203     if (!is_contained(MN->ValidKeys, NN.first())) {
 204       const SMRange &ReportLoc = NN.second.second;
 205       if (!AllowUnknownKeys) {
 206         setError(ReportLoc, Twine("unknown key '") + NN.first() + "'");
 207         break;
 208       } else
 209         reportWarning(ReportLoc, Twine("unknown key '") + NN.first() + "'");
 210     }
 211   }
 212 }
 213
 214 void Input::beginFlowMapping() { beginMapping(); }
 215
 216 void Input::endFlowMapping() { endMapping(); }
 217
 218 unsigned Input::beginSequence() {
 219   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode))
 220     return SQ->Entries.size();
 221   if (isa<EmptyHNode>(CurrentNode))
 222     return 0;
 223   // Treat case where there's a scalar "null" value as an empty sequence.
 224   if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
 225     if (isNull(SN->value()))
 226       return 0;
 227   }
 228   // Any other type of HNode is an error.
 229   setError(CurrentNode, "not a sequence");
 230   return 0;
 231 }
 232
 233 void Input::endSequence() {
 234 }
 235
 236 bool Input::preflightElement(unsigned Index, void *&SaveInfo) {
 237   if (EC)
 238     return false;
 239   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
 240     SaveInfo = CurrentNode;
 241     CurrentNode = SQ->Entries[Index].get();
 242     return true;
 243   }
 244   return false;
 245 }
 246
 247 void Input::postflightElement(void *SaveInfo) {
 248   CurrentNode = reinterpret_cast<HNode *>(SaveInfo);
 249 }
 250
 251 unsigned Input::beginFlowSequence() { return beginSequence(); }
 252
 253 bool Input::preflightFlowElement(unsigned index, void *&SaveInfo) {
 254   if (EC)
 255     return false;
 256   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
 257     SaveInfo = CurrentNode;
 258     CurrentNode = SQ->Entries[index].get();
 259     return true;
 260   }
 261   return false;
 262 }
 263
 264 void Input::postflightFlowElement(void *SaveInfo) {
 265   CurrentNode = reinterpret_cast<HNode *>(SaveInfo);
 266 }
 267
 268 void Input::endFlowSequence() {
 269 }
 270
 271 void Input::beginEnumScalar() {
 272   ScalarMatchFound = false;
 273 }
 274
 275 bool Input::matchEnumScalar(const char *Str, bool) {
 276   if (ScalarMatchFound)
 277     return false;
 278   if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
 279     if (SN->value().equals(Str)) {
 280       ScalarMatchFound = true;
 281       return true;
 282     }
 283   }
 284   return false;
 285 }
 286
 287 bool Input::matchEnumFallback() {
 288   if (ScalarMatchFound)
 289     return false;
 290   ScalarMatchFound = true;
 291   return true;
 292 }
 293
 294 void Input::endEnumScalar() {
 295   if (!ScalarMatchFound) {
 296     setError(CurrentNode, "unknown enumerated scalar");
 297   }
 298 }
 299
 300 bool Input::beginBitSetScalar(bool &DoClear) {
 301   BitValuesUsed.clear();
 302   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
 303     BitValuesUsed.insert(BitValuesUsed.begin(), SQ->Entries.size(), false);
 304   } else {
 305     setError(CurrentNode, "expected sequence of bit values");
 306   }
 307   DoClear = true;
 308   return true;
 309 }
 310
 311 bool Input::bitSetMatch(const char *Str, bool) {
 312   if (EC)
 313     return false;
 314   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
 315     unsigned Index = 0;
 316     for (auto &N : SQ->Entries) {
 317       if (ScalarHNode *SN = dyn_cast<ScalarHNode>(N.get())) {
 318         if (SN->value().equals(Str)) {
 319           BitValuesUsed[Index] = true;
 320           return true;
 321         }
 322       } else {
 323         setError(CurrentNode, "unexpected scalar in sequence of bit values");
 324       }
 325       ++Index;
 326     }
 327   } else {
 328     setError(CurrentNode, "expected sequence of bit values");
 329   }
 330   return false;
 331 }
 332
 333 void Input::endBitSetScalar() {
 334   if (EC)
 335     return;
 336   if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
 337     assert(BitValuesUsed.size() == SQ->Entries.size());
 338     for (unsigned i = 0; i < SQ->Entries.size(); ++i) {
 339       if (!BitValuesUsed[i]) {
 340         setError(SQ->Entries[i].get(), "unknown bit value");
 341         return;
 342       }
 343     }
 344   }
 345 }
 346
 347 void Input::scalarString(StringRef &S, QuotingType) {
 348   if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
 349     S = SN->value();
 350   } else {
 351     setError(CurrentNode, "unexpected scalar");
 352   }
 353 }
 354
 355 void Input::blockScalarString(StringRef &S) { scalarString(S, QuotingType::None); }
 356
 357 void Input::scalarTag(std::string &Tag) {
 358   Tag = CurrentNode->_node->getVerbatimTag();
 359 }
 360
 361 void Input::setError(HNode *hnode, const Twine &message) {
 362   assert(hnode && "HNode must not be NULL");
 363   setError(hnode->_node, message);
 364 }
 365
 366 NodeKind Input::getNodeKind() {
 367   if (isa<ScalarHNode>(CurrentNode))
 368     return NodeKind::Scalar;
 369   else if (isa<MapHNode>(CurrentNode))
 370     return NodeKind::Map;
 371   else if (isa<SequenceHNode>(CurrentNode))
 372     return NodeKind::Sequence;
 373   llvm_unreachable("Unsupported node kind");
 374 }
 375
 376 void Input::setError(Node *node, const Twine &message) {
 377   Strm->printError(node, message);
 378   EC = make_error_code(errc::invalid_argument);
 379 }
 380
 381 void Input::setError(const SMRange &range, const Twine &message) {
 382   Strm->printError(range, message);
 383   EC = make_error_code(errc::invalid_argument);
 384 }
 385
 386 void Input::reportWarning(HNode *hnode, const Twine &message) {
 387   assert(hnode && "HNode must not be NULL");
 388   Strm->printError(hnode->_node, message, SourceMgr::DK_Warning);
 389 }
 390
 391 void Input::reportWarning(Node *node, const Twine &message) {
 392   Strm->printError(node, message, SourceMgr::DK_Warning);
 393 }
 394
 395 void Input::reportWarning(const SMRange &range, const Twine &message) {
 396   Strm->printError(range, message, SourceMgr::DK_Warning);
 397 }
 398
 399 std::unique_ptr<Input::HNode> Input::createHNodes(Node *N) {
 400   SmallString<128> StringStorage;
 401   if (ScalarNode *SN = dyn_cast<ScalarNode>(N)) {
 402     StringRef KeyStr = SN->getValue(StringStorage);
 403     if (!StringStorage.empty()) {
 404       // Copy string to permanent storage
 405       KeyStr = StringStorage.str().copy(StringAllocator);
 406     }
 407     return std::make_unique<ScalarHNode>(N, KeyStr);
 408   } else if (BlockScalarNode *BSN = dyn_cast<BlockScalarNode>(N)) {
 409     StringRef ValueCopy = BSN->getValue().copy(StringAllocator);
 410     return std::make_unique<ScalarHNode>(N, ValueCopy);
 411   } else if (SequenceNode *SQ = dyn_cast<SequenceNode>(N)) {
 412     auto SQHNode = std::make_unique<SequenceHNode>(N);
 413     for (Node &SN : *SQ) {
 414       auto Entry = createHNodes(&SN);
 415       if (EC)
 416         break;
 417       SQHNode->Entries.push_back(std::move(Entry));
 418     }
 419     return std::move(SQHNode);
 420   } else if (MappingNode *Map = dyn_cast<MappingNode>(N)) {
 421     auto mapHNode = std::make_unique<MapHNode>(N);
 422     for (KeyValueNode &KVN : *Map) {
 423       Node *KeyNode = KVN.getKey();
 424       ScalarNode *Key = dyn_cast_or_null<ScalarNode>(KeyNode);
 425       Node *Value = KVN.getValue();
 426       if (!Key || !Value) {
 427         if (!Key)
 428           setError(KeyNode, "Map key must be a scalar");
 429         if (!Value)
 430           setError(KeyNode, "Map value must not be empty");
 431         break;
 432       }
 433       StringStorage.clear();
 434       StringRef KeyStr = Key->getValue(StringStorage);
 435       if (!StringStorage.empty()) {
 436         // Copy string to permanent storage
 437         KeyStr = StringStorage.str().copy(StringAllocator);
 438       }
 439       auto ValueHNode = createHNodes(Value);
 440       if (EC)
 441         break;
 442       mapHNode->Mapping[KeyStr] =
 443           std::make_pair(std::move(ValueHNode), KeyNode->getSourceRange());
 444     }
 445     return std::move(mapHNode);
 446   } else if (isa<NullNode>(N)) {
 447     return std::make_unique<EmptyHNode>(N);
 448   } else {
 449     setError(N, "unknown node kind");
 450     return nullptr;
 451   }
 452 }
 453
 454 void Input::setError(const Twine &Message) {
 455   setError(CurrentNode, Message);
 456 }
 457
 458 void Input::setAllowUnknownKeys(bool Allow) { AllowUnknownKeys = Allow; }
 459
 460 bool Input::canElideEmptySequence() {
 461   return false;
 462 }
 463
 464 //===----------------------------------------------------------------------===//
 465 //  Output
 466 //===----------------------------------------------------------------------===//
 467
 468 Output::Output(raw_ostream &yout, void *context, int WrapColumn)
 469     : IO(context), Out(yout), WrapColumn(WrapColumn) {}
 470
 471 Output::~Output() = default;
 472
 473 bool Output::outputting() const {
 474   return true;
 475 }
 476
 477 void Output::beginMapping() {
 478   StateStack.push_back(inMapFirstKey);
 479   PaddingBeforeContainer = Padding;
 480   Padding = "\n";
 481 }
 482
 483 bool Output::mapTag(StringRef Tag, bool Use) {
 484   if (Use) {
 485     // If this tag is being written inside a sequence we should write the start
 486     // of the sequence before writing the tag, otherwise the tag won't be
 487     // attached to the element in the sequence, but rather the sequence itself.
 488     bool SequenceElement = false;
 489     if (StateStack.size() > 1) {
 490       auto &E = StateStack[StateStack.size() - 2];
 491       SequenceElement = inSeqAnyElement(E) || inFlowSeqAnyElement(E);
 492     }
 493     if (SequenceElement && StateStack.back() == inMapFirstKey) {
 494       newLineCheck();
 495     } else {
 496       output(" ");
 497     }
 498     output(Tag);
 499     if (SequenceElement) {
 500       // If we're writing the tag during the first element of a map, the tag
 501       // takes the place of the first element in the sequence.
 502       if (StateStack.back() == inMapFirstKey) {
 503         StateStack.pop_back();
 504         StateStack.push_back(inMapOtherKey);
 505       }
 506       // Tags inside maps in sequences should act as keys in the map from a
 507       // formatting perspective, so we always want a newline in a sequence.
 508       Padding = "\n";
 509     }
 510   }
 511   return Use;
 512 }
 513
 514 void Output::endMapping() {
 515   // If we did not map anything, we should explicitly emit an empty map
 516   if (StateStack.back() == inMapFirstKey) {
 517     Padding = PaddingBeforeContainer;
 518     newLineCheck();
 519     output("{}");
 520     Padding = "\n";
 521   }
 522   StateStack.pop_back();
 523 }
 524
 525 std::vector<StringRef> Output::keys() {
 526   report_fatal_error("invalid call");
 527 }
 528
 529 bool Output::preflightKey(const char *Key, bool Required, bool SameAsDefault,
 530                           bool &UseDefault, void *&) {
 531   UseDefault = false;
 532   if (Required || !SameAsDefault || WriteDefaultValues) {
 533     auto State = StateStack.back();
 534     if (State == inFlowMapFirstKey || State == inFlowMapOtherKey) {
 535       flowKey(Key);
 536     } else {
 537       newLineCheck();
 538       paddedKey(Key);
 539     }
 540     return true;
 541   }
 542   return false;
 543 }
 544
 545 void Output::postflightKey(void *) {
 546   if (StateStack.back() == inMapFirstKey) {
 547     StateStack.pop_back();
 548     StateStack.push_back(inMapOtherKey);
 549   } else if (StateStack.back() == inFlowMapFirstKey) {
 550     StateStack.pop_back();
 551     StateStack.push_back(inFlowMapOtherKey);
 552   }
 553 }
 554
 555 void Output::beginFlowMapping() {
 556   StateStack.push_back(inFlowMapFirstKey);
 557   newLineCheck();
 558   ColumnAtMapFlowStart = Column;
 559   output("{ ");
 560 }
 561
 562 void Output::endFlowMapping() {
 563   StateStack.pop_back();
 564   outputUpToEndOfLine(" }");
 565 }
 566
 567 void Output::beginDocuments() {
 568   outputUpToEndOfLine("---");
 569 }
 570
 571 bool Output::preflightDocument(unsigned index) {
 572   if (index > 0)
 573     outputUpToEndOfLine("\n---");
 574   return true;
 575 }
 576
 577 void Output::postflightDocument() {
 578 }
 579
 580 void Output::endDocuments() {
 581   output("\n...\n");
 582 }
 583
 584 unsigned Output::beginSequence() {
 585   StateStack.push_back(inSeqFirstElement);
 586   PaddingBeforeContainer = Padding;
 587   Padding = "\n";
 588   return 0;
 589 }
 590
 591 void Output::endSequence() {
 592   // If we did not emit anything, we should explicitly emit an empty sequence
 593   if (StateStack.back() == inSeqFirstElement) {
 594     Padding = PaddingBeforeContainer;
 595     newLineCheck(/*EmptySequence=*/true);
 596     output("[]");
 597     Padding = "\n";
 598   }
 599   StateStack.pop_back();
 600 }
 601
 602 bool Output::preflightElement(unsigned, void *&) {
 603   return true;
 604 }
 605
 606 void Output::postflightElement(void *) {
 607   if (StateStack.back() == inSeqFirstElement) {
 608     StateStack.pop_back();
 609     StateStack.push_back(inSeqOtherElement);
 610   } else if (StateStack.back() == inFlowSeqFirstElement) {
 611     StateStack.pop_back();
 612     StateStack.push_back(inFlowSeqOtherElement);
 613   }
 614 }
 615
 616 unsigned Output::beginFlowSequence() {
 617   StateStack.push_back(inFlowSeqFirstElement);
 618   newLineCheck();
 619   ColumnAtFlowStart = Column;
 620   output("[ ");
 621   NeedFlowSequenceComma = false;
 622   return 0;
 623 }
 624
 625 void Output::endFlowSequence() {
 626   StateStack.pop_back();
 627   outputUpToEndOfLine(" ]");
 628 }
 629
 630 bool Output::preflightFlowElement(unsigned, void *&) {
 631   if (NeedFlowSequenceComma)
 632     output(", ");
 633   if (WrapColumn && Column > WrapColumn) {
 634     output("\n");
 635     for (int i = 0; i < ColumnAtFlowStart; ++i)
 636       output(" ");
 637     Column = ColumnAtFlowStart;
 638     output("  ");
 639   }
 640   return true;
 641 }
 642
 643 void Output::postflightFlowElement(void *) {
 644   NeedFlowSequenceComma = true;
 645 }
 646
 647 void Output::beginEnumScalar() {
 648   EnumerationMatchFound = false;
 649 }
 650
 651 bool Output::matchEnumScalar(const char *Str, bool Match) {
 652   if (Match && !EnumerationMatchFound) {
 653     newLineCheck();
 654     outputUpToEndOfLine(Str);
 655     EnumerationMatchFound = true;
 656   }
 657   return false;
 658 }
 659
 660 bool Output::matchEnumFallback() {
 661   if (EnumerationMatchFound)
 662     return false;
 663   EnumerationMatchFound = true;
 664   return true;
 665 }
 666
 667 void Output::endEnumScalar() {
 668   if (!EnumerationMatchFound)
 669     llvm_unreachable("bad runtime enum value");
 670 }
 671
 672 bool Output::beginBitSetScalar(bool &DoClear) {
 673   newLineCheck();
 674   output("[ ");
 675   NeedBitValueComma = false;
 676   DoClear = false;
 677   return true;
 678 }
 679
 680 bool Output::bitSetMatch(const char *Str, bool Matches) {
 681   if (Matches) {
 682     if (NeedBitValueComma)
 683       output(", ");
 684     output(Str);
 685     NeedBitValueComma = true;
 686   }
 687   return false;
 688 }
 689
 690 void Output::endBitSetScalar() {
 691   outputUpToEndOfLine(" ]");
 692 }
 693
 694 void Output::scalarString(StringRef &S, QuotingType MustQuote) {
 695   newLineCheck();
 696   if (S.empty()) {
 697     // Print '' for the empty string because leaving the field empty is not
 698     // allowed.
 699     outputUpToEndOfLine("''");
 700     return;
 701   }
 702   if (MustQuote == QuotingType::None) {
 703     // Only quote if we must.
 704     outputUpToEndOfLine(S);
 705     return;
 706   }
 707
 708   const char *const Quote = MustQuote == QuotingType::Single ? "'" : "\"";
 709   output(Quote); // Starting quote.
 710
 711   // When using double-quoted strings (and only in that case), non-printable characters may be
 712   // present, and will be escaped using a variety of unicode-scalar and special short-form
 713   // escapes. This is handled in yaml::escape.
 714   if (MustQuote == QuotingType::Double) {
 715     output(yaml::escape(S, /* EscapePrintable= */ false));
 716     outputUpToEndOfLine(Quote);
 717     return;
 718   }
 719
 720   unsigned i = 0;
 721   unsigned j = 0;
 722   unsigned End = S.size();
 723   const char *Base = S.data();
 724
 725   // When using single-quoted strings, any single quote ' must be doubled to be escaped.
 726   while (j < End) {
 727     if (S[j] == '\'') {                    // Escape quotes.
 728       output(StringRef(&Base[i], j - i));  // "flush".
 729       output(StringLiteral("''"));         // Print it as ''
 730       i = j + 1;
 731     }
 732     ++j;
 733   }
 734   output(StringRef(&Base[i], j - i));
 735   outputUpToEndOfLine(Quote); // Ending quote.
 736 }
 737
 738 void Output::blockScalarString(StringRef &S) {
 739   if (!StateStack.empty())
 740     newLineCheck();
 741   output(" |");
 742   outputNewLine();
 743
 744   unsigned Indent = StateStack.empty() ? 1 : StateStack.size();
 745
 746   auto Buffer = MemoryBuffer::getMemBuffer(S, "", false);
 747   for (line_iterator Lines(*Buffer, false); !Lines.is_at_end(); ++Lines) {
 748     for (unsigned I = 0; I < Indent; ++I) {
 749       output("  ");
 750     }
 751     output(*Lines);
 752     outputNewLine();
 753   }
 754 }
 755
 756 void Output::scalarTag(std::string &Tag) {
 757   if (Tag.empty())
 758     return;
 759   newLineCheck();
 760   output(Tag);
 761   output(" ");
 762 }
 763
 764 void Output::setError(const Twine &message) {
 765 }
 766
 767 bool Output::canElideEmptySequence() {
 768   // Normally, with an optional key/value where the value is an empty sequence,
 769   // the whole key/value can be not written.  But, that produces wrong yaml
 770   // if the key/value is the only thing in the map and the map is used in
 771   // a sequence.  This detects if the this sequence is the first key/value
 772   // in map that itself is embedded in a sequence.
 773   if (StateStack.size() < 2)
 774     return true;
 775   if (StateStack.back() != inMapFirstKey)
 776     return true;
 777   return !inSeqAnyElement(StateStack[StateStack.size() - 2]);
 778 }
 779
 780 void Output::output(StringRef s) {
 781   Column += s.size();
 782   Out << s;
 783 }
 784
 785 void Output::outputUpToEndOfLine(StringRef s) {
 786   output(s);
 787   if (StateStack.empty() || (!inFlowSeqAnyElement(StateStack.back()) &&
 788                              !inFlowMapAnyKey(StateStack.back())))
 789     Padding = "\n";
 790 }
 791
 792 void Output::outputNewLine() {
 793   Out << "\n";
 794   Column = 0;
 795 }
 796
 797 // if seq at top, indent as if map, then add "- "
 798 // if seq in middle, use "- " if firstKey, else use "  "
 799 //
 800
 801 void Output::newLineCheck(bool EmptySequence) {
 802   if (Padding != "\n") {
 803     output(Padding);
 804     Padding = {};
 805     return;
 806   }
 807   outputNewLine();
 808   Padding = {};
 809
 810   if (StateStack.size() == 0 || EmptySequence)
 811     return;
 812
 813   unsigned Indent = StateStack.size() - 1;
 814   bool OutputDash = false;
 815
 816   if (StateStack.back() == inSeqFirstElement ||
 817       StateStack.back() == inSeqOtherElement) {
 818     OutputDash = true;
 819   } else if ((StateStack.size() > 1) &&
 820              ((StateStack.back() == inMapFirstKey) ||
 821               inFlowSeqAnyElement(StateStack.back()) ||
 822               (StateStack.back() == inFlowMapFirstKey)) &&
 823              inSeqAnyElement(StateStack[StateStack.size() - 2])) {
 824     --Indent;
 825     OutputDash = true;
 826   }
 827
 828   for (unsigned i = 0; i < Indent; ++i) {
 829     output("  ");
 830   }
 831   if (OutputDash) {
 832     output("- ");
 833   }
 834 }
 835
 836 void Output::paddedKey(StringRef key) {
 837   output(key);
 838   output(":");
 839   const char *spaces = "                ";
 840   if (key.size() < strlen(spaces))
 841     Padding = &spaces[key.size()];
 842   else
 843     Padding = " ";
 844 }
 845
 846 void Output::flowKey(StringRef Key) {
 847   if (StateStack.back() == inFlowMapOtherKey)
 848     output(", ");
 849   if (WrapColumn && Column > WrapColumn) {
 850     output("\n");
 851     for (int I = 0; I < ColumnAtMapFlowStart; ++I)
 852       output(" ");
 853     Column = ColumnAtMapFlowStart;
 854     output("  ");
 855   }
 856   output(Key);
 857   output(": ");
 858 }
 859
 860 NodeKind Output::getNodeKind() { report_fatal_error("invalid call"); }
 861
 862 bool Output::inSeqAnyElement(InState State) {
 863   return State == inSeqFirstElement || State == inSeqOtherElement;
 864 }
 865
 866 bool Output::inFlowSeqAnyElement(InState State) {
 867   return State == inFlowSeqFirstElement || State == inFlowSeqOtherElement;
 868 }
 869
 870 bool Output::inMapAnyKey(InState State) {
 871   return State == inMapFirstKey || State == inMapOtherKey;
 872 }
 873
 874 bool Output::inFlowMapAnyKey(InState State) {
 875   return State == inFlowMapFirstKey || State == inFlowMapOtherKey;
 876 }
 877
 878 //===----------------------------------------------------------------------===//
 879 //  traits for built-in types
 880 //===----------------------------------------------------------------------===//
 881
 882 void ScalarTraits<bool>::output(const bool &Val, void *, raw_ostream &Out) {
 883   Out << (Val ? "true" : "false");
 884 }
 885
 886 StringRef ScalarTraits<bool>::input(StringRef Scalar, void *, bool &Val) {
 887   if (llvm::Optional<bool> Parsed = parseBool(Scalar)) {
 888     Val = *Parsed;
 889     return StringRef();
 890   }
 891   return "invalid boolean";
 892 }
 893
 894 void ScalarTraits<StringRef>::output(const StringRef &Val, void *,
 895                                      raw_ostream &Out) {
 896   Out << Val;
 897 }
 898
 899 StringRef ScalarTraits<StringRef>::input(StringRef Scalar, void *,
 900                                          StringRef &Val) {
 901   Val = Scalar;
 902   return StringRef();
 903 }
 904
 905 void ScalarTraits<std::string>::output(const std::string &Val, void *,
 906                                        raw_ostream &Out) {
 907   Out << Val;
 908 }
 909
 910 StringRef ScalarTraits<std::string>::input(StringRef Scalar, void *,
 911                                            std::string &Val) {
 912   Val = Scalar.str();
 913   return StringRef();
 914 }
 915
 916 void ScalarTraits<uint8_t>::output(const uint8_t &Val, void *,
 917                                    raw_ostream &Out) {
 918   // use temp uin32_t because ostream thinks uint8_t is a character
 919   uint32_t Num = Val;
 920   Out << Num;
 921 }
 922
 923 StringRef ScalarTraits<uint8_t>::input(StringRef Scalar, void *, uint8_t &Val) {
 924   unsigned long long n;
 925   if (getAsUnsignedInteger(Scalar, 0, n))
 926     return "invalid number";
 927   if (n > 0xFF)
 928     return "out of range number";
 929   Val = n;
 930   return StringRef();
 931 }
 932
 933 void ScalarTraits<uint16_t>::output(const uint16_t &Val, void *,
 934                                     raw_ostream &Out) {
 935   Out << Val;
 936 }
 937
 938 StringRef ScalarTraits<uint16_t>::input(StringRef Scalar, void *,
 939                                         uint16_t &Val) {
 940   unsigned long long n;
 941   if (getAsUnsignedInteger(Scalar, 0, n))
 942     return "invalid number";
 943   if (n > 0xFFFF)
 944     return "out of range number";
 945   Val = n;
 946   return StringRef();
 947 }
 948
 949 void ScalarTraits<uint32_t>::output(const uint32_t &Val, void *,
 950                                     raw_ostream &Out) {
 951   Out << Val;
 952 }
 953
 954 StringRef ScalarTraits<uint32_t>::input(StringRef Scalar, void *,
 955                                         uint32_t &Val) {
 956   unsigned long long n;
 957   if (getAsUnsignedInteger(Scalar, 0, n))
 958     return "invalid number";
 959   if (n > 0xFFFFFFFFUL)
 960     return "out of range number";
 961   Val = n;
 962   return StringRef();
 963 }
 964
 965 void ScalarTraits<uint64_t>::output(const uint64_t &Val, void *,
 966                                     raw_ostream &Out) {
 967   Out << Val;
 968 }
 969
 970 StringRef ScalarTraits<uint64_t>::input(StringRef Scalar, void *,
 971                                         uint64_t &Val) {
 972   unsigned long long N;
 973   if (getAsUnsignedInteger(Scalar, 0, N))
 974     return "invalid number";
 975   Val = N;
 976   return StringRef();
 977 }
 978
 979 void ScalarTraits<int8_t>::output(const int8_t &Val, void *, raw_ostream &Out) {
 980   // use temp in32_t because ostream thinks int8_t is a character
 981   int32_t Num = Val;
 982   Out << Num;
 983 }
 984
 985 StringRef ScalarTraits<int8_t>::input(StringRef Scalar, void *, int8_t &Val) {
 986   long long N;
 987   if (getAsSignedInteger(Scalar, 0, N))
 988     return "invalid number";
 989   if ((N > 127) || (N < -128))
 990     return "out of range number";
 991   Val = N;
 992   return StringRef();
 993 }
 994
 995 void ScalarTraits<int16_t>::output(const int16_t &Val, void *,
 996                                    raw_ostream &Out) {
 997   Out << Val;
 998 }
 999
1000 StringRef ScalarTraits<int16_t>::input(StringRef Scalar, void *, int16_t &Val) {
1001   long long N;
1002   if (getAsSignedInteger(Scalar, 0, N))
1003     return "invalid number";
1004   if ((N > INT16_MAX) || (N < INT16_MIN))
1005     return "out of range number";
1006   Val = N;
1007   return StringRef();
1008 }
1009
1010 void ScalarTraits<int32_t>::output(const int32_t &Val, void *,
1011                                    raw_ostream &Out) {
1012   Out << Val;
1013 }
1014
1015 StringRef ScalarTraits<int32_t>::input(StringRef Scalar, void *, int32_t &Val) {
1016   long long N;
1017   if (getAsSignedInteger(Scalar, 0, N))
1018     return "invalid number";
1019   if ((N > INT32_MAX) || (N < INT32_MIN))
1020     return "out of range number";
1021   Val = N;
1022   return StringRef();
1023 }
1024
1025 void ScalarTraits<int64_t>::output(const int64_t &Val, void *,
1026                                    raw_ostream &Out) {
1027   Out << Val;
1028 }
1029
1030 StringRef ScalarTraits<int64_t>::input(StringRef Scalar, void *, int64_t &Val) {
1031   long long N;
1032   if (getAsSignedInteger(Scalar, 0, N))
1033     return "invalid number";
1034   Val = N;
1035   return StringRef();
1036 }
1037
1038 void ScalarTraits<double>::output(const double &Val, void *, raw_ostream &Out) {
1039   Out << format("%g", Val);
1040 }
1041
1042 StringRef ScalarTraits<double>::input(StringRef Scalar, void *, double &Val) {
1043   if (to_float(Scalar, Val))
1044     return StringRef();
1045   return "invalid floating point number";
1046 }
1047
1048 void ScalarTraits<float>::output(const float &Val, void *, raw_ostream &Out) {
1049   Out << format("%g", Val);
1050 }
1051
1052 StringRef ScalarTraits<float>::input(StringRef Scalar, void *, float &Val) {
1053   if (to_float(Scalar, Val))
1054     return StringRef();
1055   return "invalid floating point number";
1056 }
1057
1058 void ScalarTraits<Hex8>::output(const Hex8 &Val, void *, raw_ostream &Out) {
1059   Out << format("0x%" PRIX8, (uint8_t)Val);
1060 }
1061
1062 StringRef ScalarTraits<Hex8>::input(StringRef Scalar, void *, Hex8 &Val) {
1063   unsigned long long n;
1064   if (getAsUnsignedInteger(Scalar, 0, n))
1065     return "invalid hex8 number";
1066   if (n > 0xFF)
1067     return "out of range hex8 number";
1068   Val = n;
1069   return StringRef();
1070 }
1071
1072 void ScalarTraits<Hex16>::output(const Hex16 &Val, void *, raw_ostream &Out) {
1073   Out << format("0x%" PRIX16, (uint16_t)Val);
1074 }
1075
1076 StringRef ScalarTraits<Hex16>::input(StringRef Scalar, void *, Hex16 &Val) {
1077   unsigned long long n;
1078   if (getAsUnsignedInteger(Scalar, 0, n))
1079     return "invalid hex16 number";
1080   if (n > 0xFFFF)
1081     return "out of range hex16 number";
1082   Val = n;
1083   return StringRef();
1084 }
1085
1086 void ScalarTraits<Hex32>::output(const Hex32 &Val, void *, raw_ostream &Out) {
1087   Out << format("0x%" PRIX32, (uint32_t)Val);
1088 }
1089
1090 StringRef ScalarTraits<Hex32>::input(StringRef Scalar, void *, Hex32 &Val) {
1091   unsigned long long n;
1092   if (getAsUnsignedInteger(Scalar, 0, n))
1093     return "invalid hex32 number";
1094   if (n > 0xFFFFFFFFUL)
1095     return "out of range hex32 number";
1096   Val = n;
1097   return StringRef();
1098 }
1099
1100 void ScalarTraits<Hex64>::output(const Hex64 &Val, void *, raw_ostream &Out) {
1101   Out << format("0x%" PRIX64, (uint64_t)Val);
1102 }
1103
1104 StringRef ScalarTraits<Hex64>::input(StringRef Scalar, void *, Hex64 &Val) {
1105   unsigned long long Num;
1106   if (getAsUnsignedInteger(Scalar, 0, Num))
1107     return "invalid hex64 number";
1108   Val = Num;
1109   return StringRef();
1110 }
1111
1112 void ScalarTraits<VersionTuple>::output(const VersionTuple &Val, void *,
1113                                         llvm::raw_ostream &Out) {
1114   Out << Val.getAsString();
1115 }
1116
1117 StringRef ScalarTraits<VersionTuple>::input(StringRef Scalar, void *,
1118                                             VersionTuple &Val) {
1119   if (Val.tryParse(Scalar))
1120     return "invalid version format";
1121   return StringRef();
1122 }